Cumulative experience of loneliness and frailty progression: A prospective cohort study

Loneliness undergoes changes over time, but its cumulative effect on frailty is unknown. We aimed to investigate the association between cumulative loneliness and frailty.

3781 participants from English Longitudinal Study of Ageing (ELSA) waves 2 to 9 were involved. Cumulative loneliness was evaluated by Cumulative Loneliness Index-Sum (CLI-Sum); Cumulative Loneliness Index-AUC (CLI-AUC) and Time-Weighted Average Loneliness Index (TWA-LI). Thirty-items frailty index (FI) was used to assess frailty status. Multivariate linear mixed models and cox proportional hazards models were utilized.

Participants in the highest quartile (Quartile 4) of cumulative loneliness exhibited worse frailty compared to Quartile 1: Quartile 4 groups showed faster annual increases in FI, the β (95%CI) were as follows: 0.28 (0.12-0.45) for CLI-Sum, 0.20 (0.04-0.37) for CLI-AUC, and 0.28 (0.12-0.44) for TWA-LI. In addition, Quartile 4 groups associated with higher frailty risk, the hazard ratios (95%CI) were as follows: 1.53 (1.24-1.89) for CLI-Sum; 1.65 (1.34-2.02) for CLI-AUC and 1.61 (1.31-1.99) for TWA-LI and all P trend <0.05.

Cumulative loneliness can significantly accelerate the frailty progression. Our study emphasizes the significance of improving duration of loneliness.